The present disclosure relates to a 3-dimensional operation input apparatus for operating a pointer on a screen, a control apparatus for controlling the pointer in accordance with operational information, a control system including those apparatuses, a control method, and a handheld apparatus.
Pointing devices, particularly a mouse and a touchpad, are used as controllers for GUIs (Graphical User Interfaces) widely used in PCs (Personal Computers). Not just as HIs (Human Interfaces) of PCs as in related art, the GUIs are now starting to be used as an interface for AV equipment and game devices used in living rooms etc. with, for example, televisions as image media. Various pointing devices that a user is capable of operating 3-dimensionally are proposed as controllers for the GUIs of this type (see, for example, Patent Documents 1 and 2).
Patent Document 1 discloses an input apparatus including angular velocity gyroscopes of two axes, that is, two angular velocity sensors. Each angular velocity sensor is a vibration-type angular velocity sensor. For example, upon application of an angular velocity with respect to a vibrating body piezoelectrically vibrating at a resonance frequency, Coriolis force is generated in a direction orthogonal to a vibration direction of the vibrating body. The Coriolis force is in proportion to the angular velocity, so detection of the Coriolis force leads to detection of the angular velocity. The input apparatus of Patent Document 1 detects angular velocities about two orthogonal axes by the angular velocity sensors, generates, in accordance with the angular velocities, a command signal as positional information of a cursor or the like displayed by a display means, and transmits it to the control apparatus.
Patent Document 2 discloses a pen-type input apparatus including three acceleration sensors (of three axes) and three angular velocity sensors (of three axes) (gyro). The pen-type input apparatus executes various operations based on signals obtained by the three acceleration sensors and the three angular velocity sensors, to thus calculate a positional angle of the pen-type input apparatus.
Generally, each of the acceleration sensors detects not only an acceleration at a time the input apparatus is operated by the user, but also a gravity acceleration. Because gravity that acts on the input apparatus and an inertial force of the input apparatus generated when the input apparatus is moved are of the same physical amount, it is impossible for the input apparatus to make a distinction therebetween. When the user holds the input apparatus while tilting it from its original position, for example, a component force of the gravity acceleration corresponding to the tilt acts on the acceleration sensors corresponding to respective axes, and the acceleration sensors inadvertently detect the force.
However, the pen-type input apparatus of Patent Document 2 above detects triaxial angular velocities and accelerations in triaxial directions, that is, detects amounts in all 6 degrees of freedom, thus solving the problems on the inertial force and the gravity.
Patent Document 1: Japanese Patent Application Laid-open No. 2001-56743 (paragraphs [0030] and [0031], FIG. 3)
Patent Document 2: Japanese Patent No. 3,748,483 (paragraphs [0033] and [0041], FIG. 1)
Patent Document 3: Japanese Patent Translation Publication No. 2007-509448 (paragraphs [0019], [0021], [0029], and [0034], FIG. 5)
Because three acceleration sensors and three angular velocity sensors are used in the pen-type input apparatus of Patent Document 2, a structure thereof is complex and a calculation amount becomes large, thus resulting in a fear that a delay time may occur. As a result, a temporal deviation occurs between an operation timing of the user and an operation timing of the GUI, thus making the user feel awkward. Moreover, an increase in the calculation amount leads to an increase in power consumption. For a built-in-battery-type input apparatus, for example, the problem on power consumption is important.
When a high-speed CPU or MPU is used for eliminating the delay time above, there is a problem that power consumption and costs additionally increase.
Further, since the pen-type input apparatus of Patent Document 2 includes six sensors, a CPU or an A/D converter that includes six A/D (Analog/Digital) ports becomes necessary, thus resulting in a problem that a circuit structure becomes complex and costs are further increased.
Furthermore, because the pen-type input apparatus of Patent Document 2 requires integration terms of accelerations in operations, there is also a problem that integration errors are accumulated. For solving this problem, resetting integration values under a specific condition has been proposed, but there is also a problem that there is no guarantee that a reset condition can be obtained at time intervals necessary for suppressing integration errors within a level non-influential for practical use.